A rotating lamp employing an incandescent lamp for a light source is known in general. However, the rotating lamp employing an incandescent lamp is disadvantageously burned out in a short period, consumes high power and requires much labor for maintenance/management.
Therefore, an LED device has recently been employed as the light source for a rotating lamp. For example, Japanese Patent Laying-Open No. 2002-163903 (Patent Document 1) describes an exemplary rotating lamp employing LED devices as a light source.
In the rotating lamp described in Japanese Patent Laying-Open No. 2002-163903, a plurality of LED devices are radially arranged on the upper and lower surfaces of a discoidal holder for forming a light source, and a cylindrical rotating reflector is provided around this light source. In the rotating lamp having this structure, the reflector rotates around the light source constituted of the LED devices, to horizontally reflect light emitted from the LED devices.
The light reflected by the reflector is substantially parallel, and hence it is necessary to ensure a sectional area of the reflecting light path in order to deliver the reflected light over a wide range. Therefore, the reflector has an opening of a prescribed size in general. Thus, a large number of LED devices are located on a side of the reflector closer to the opening. Consequently, the light emitted from the LED devices is directly radiated outward at a high rate.
Patent Document 1: Japanese Patent Laying-Open No. 2002-163903